Terahertz

I get asked the question a lot, what do I do? Now anyone who works in a scientific and technical field knows the problem with this question. And that is that half the time we don’t even know what we do!

For the short answer, I reply “I shoot [tag]lasers[/tag] at stuff”. But that doesn’t really say anything at all, does it?

For people with a little more technical knowledge, I might talk about how I make wire grids that are a tenth the width of your hair in the University of Alberta’s [tag]Nanofab[/tag] and then shoot them with lasers. But that’s still not really saying anything.

I could go deeper and say that I’ve made grids of gold wires that range from 5 mm long wires to arrays of 10 micron by 10 micron squares (and various lengths in between), and that I’m trying to use the laser to see how electricity flows in them. But I still wouldn’t be at the meat of it yet.

If I wanted to be a really elitist bastard I could give a jargony talk about how I’m making [tag]subwavelength[/tag] [tag]metamaterials[/tag] for probing using terahertz-time domain spectroscopy in order to extract the complex [tag]conductivity[/tag] of the devices. I could also talk about how I might be observing negative differential conductivity and various resonances. But then I might just be hiding whether or not I know what’s going on (hint electrons are going backwards).

I could also talk about the laser system, which actually is four lasers creating a 1 kHz, 500 ?J, 100 fs (10^-15 s long) pulse, which can ionize air due to it’s large instantaneous intensities. And how we use that pulse and a second-order non-linearity in a crystal of (110) Zinc-Telluride to generate terahertz radiation by the process known as optical rectification. And that detection of this radiation is completed using electro-optic sampling. But all of this would take a senior level physics course to really grasp (as I’m just finally getting it all, and I’ve been working here for 3 years).

So the big problem here, is that I have a highly specialized region of physics – that is [tag]ultrafast[/tag] spectroscopy in condensed matter physics, doing terahertz conductivity measurements of metamaterials – which is quite far removed from the basic freshman and especially high-school physics, and that when I visit with old friends or family, or basically anyone outside my lab, I have to find some way to convey that there is a point to what I’m doing. I can’t say I’m entirely sure what the point is, but the research is cool (to me), and potentially could be useful for some future application, or at the very least for understanding some weird systems that are out there.

Finally, I could also say that I come in, spend 15 minutes starting the laser, wait 15 minutes for it to warm up, spend 10-30 minutes aligning a setup and then spend the rest of the day pushing a big “SCAN” button once every fifteen minutes after moving a couple knobs to adjust my sample around. In the downtime while stuff scans I play on the internet for long periods of time, periodically checking to see if the data is reasonable. And then most days that I don’t have the laser (which is 60-80% of them) I either play with spreadsheets to make data look reasonable, or just plain screw around on the internet some more. But if I put it that way, it sounds less cool, and more monotonous.

So when asked, what do I do, I usually stick with “lasers”.

[tags]science, carnivals, terahertz[/tags]